[ntp:questions] Start of new GPS 1024 week epoch
david-taylor at blueyonder.co.uk.invalid
Fri Aug 16 13:34:34 UTC 2013
On 16/08/2013 13:02, John Hasler wrote:
> David Taylor writes:
>> A pity that they haven't been able to find two or three spare bits to
>> reduce the 1024 week ambiguity to nearer a half-century or even 100
> From the Wikipedia article:
> To determine the current Gregorian date, a GPS receiver must be
> provided with the approximate date (to within 3,584 days) to correctly
> translate the GPS date signal. To address this concern the modernized
> GPS navigation message uses a 13-bit field that only repeats every
> 8,192 weeks (157 years), thus lasting until the year 2137 (157 years
> after GPS week zero).
Oh, that /is/ good news, John! Many thanks. I couldn't see that from a
quick scan of the referenced documents, so that's most helpful to know.
I wonder whether there is any way to determine which satellites are
sending this modernised message, perhaps they all do, or whether a
particular receiver is using the full 13-bit field? It's something I've
not seen listed in various specifications I've read, but perhaps it's
taken for granted after a certain date?
More information about the questions